Explanation:

User Access Administrator can only assign access to other users
https://docs.microsoft.com/en-us/azure/role-based-access-control/rbac-and-directory-admin-roles Virtual Machine Contributor can Manage VMs, which includes deleting VMs too.
https://docs.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#virtual-machine-contributor
https://docs.microsoft.com/en-us/answers/questions/350635/can-virtual-machine-contributor-create-vm.html